Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1999-07-28
2003-06-17
Sellers, Robert E. L. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C523S467000, C525S111500, C525S117000
Reexamination Certificate
active
06579936
ABSTRACT:
BACKGROUND ART
1. Field of the Invention
The present application relates to polyarylenesulfide resin compositions having a dramatically improved adhesiveness with regard to a cured epoxy resin, while retaining characteristic properties of polyarylenesulfide resins such as heat resistance and chemical resistance, and relates practically to useful polyarylenesulfide resin compositions in a wide range of industrial fields, such as an ignition coil case for cars used by sealing the ignition coil in the coil case made of the polyarylenesulfide resin with an epoxy resin composition; and a coil case in a so-called “distributorless ignition system (hereinafter, abbreviated as “DLI”) which is produced by integrating the plug and an ignition coil; and furthermore relates to electric and electronic components such as epoxy resin sealed type semiconductor devices.
2. Background Art
Recently, polyarylenesulfide (hereinafter, abbreviated as “PAS”) has attracted attention as an excellent engineering, plastic having superior heat and chemical resistances.
One of the application fields of the PAS resin utilizing these features is producing various electronic and electric components by sealing various electronic and electric elements in casings made of the PAS resin composition formed in advance by injection molding. That is, in order to develop a new technique for producing electronic and electric components (especially, ignition coils for DLI), semiconductor elements or coils are first mounted in a casing made of PAS resin, uncured epoxy resin is poured in the casing for sealing these elements or coils, and the epoxy resin is finally cured by, for example, heat treatment for sealing these semiconductor elements or coils into the casing.
When the PAS resin is used for such applications, it is necessary for the PAS resin products to be provided with a superior long-term adhesiveness to the epoxy resin at wide ranges of usage temperatures, in addition to the intrinsic characteristics such as long-term heat and chemical resistance properties. Practically, it is required that the PAS resin products sealed by epoxy resin do not peel off from the epoxy sealant, even when the PAS resin products sealed by epoxy resin is repeatedly used in a temperature range of −40° C. to 140° C. As a matter of fact, since the PAS resin is intrinsically interior in adhesiveness to epoxy resin, and the adhesion is weak even if it is reinforced by glass fibers or the like, the PAS resin has been considered not suitable for use for sealing applications with epoxy resins.
In order to improve the adhesion of the PAS resin with the epoxy resin, Japanese Patent Application. First Publication No. Hei 9-3326, discloses a technique for improving the adhesion by addition of &agr;-olefine/&agr;,&bgr;-unsaturated carboxylic acid glycidylester copolymer and an amide carboxylic acid-type wax to the PAS resin for relieving stress caused at an interface between the PAS resin and the epoxy resin at the time of heating and cooling.
However, the PAS resin composition disclosed in Japanese Patent Application, First Publication No. Hei 9-3326, does not exhibit a satisfactory adhesiveness with the epoxy resin and generation of cracks are observed in the heating and cooling cycles, which means that conventional PAS resins are not sufficient to satisfy the level for practical use.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a PAS resin which has an dramatically improved adhesion strength with the epoxy resin during heating and cooling operations, while retaining its intrinsic superior heat and chemical resistances, and which has an improved crack resistance in heating and cooling cycles by incorporating a resin for improving the impact resistance.
The inventors of the present invention have carried out a series of studies for solving the above problems, and they have completed the present invention by discovering that the adhesiveness of the PAS resin can be dramatically improved by incorporating a bisphenol-type epoxy resin and an oxazoline-group-containing amorphous polymer, and that a superior crack resistance can be additionally provided to the PAS resin by incorporating a bisphenol-type epoxy resin, an oxazoline-group-containing copolymer, and an impact resistance improving resin.
That is, the present invention relates to a polyarylenesulfide resin composition, wherein the polyarylenesulfide composition essentially contains polyarylenesulfide resin (A), bisphenol-type epoxy resin (B), and oxazoline-group-containing amorphous polymer (C).
Although there is not particular limitation on polyarylenesulfide resin (A), it is preferable for the polyarylenesulfide (A) to have repetitive structural units expressed by a general formula 1 [—Ar—S—] (in the formula, —Ar— represents divalent aromatic group including at least one six-membered ring of carbon) as the main structural units, and it is more preferable for the polyarylenesulfide to contain more than 70 mol % of such structural units shown in the general formula 1 from the point of view of heat and chemical resistances.
Among polyarylenesulfide compositions containing more than 70 mol % of structural units expressed by the general formula 1, polyphenylene sulfide (hereinafter, abbreviated as “PPS”) containing repetitive structural units expressed by the general formula 2 [-&phgr;-S—] is preferable, and it is particularly preferable for a polymer to contain more than 70 mol % respective structural units expressed by the general formula 2 from the point of view of high mechanical strength which is a characteristic property for a crystalline polymer and also from point of view of toughness and the chemical resistance.
Examples of copolymer components having the structural unit in the polyarylenesulfide resin (A) expressed by the general formula 1 include couplings such as a metha-coupling, ether-coupling, sulfonic-, sulfonic-coupling, sulfideketone-coupling, biphenyl-coupling, substituted phenylsulfide-coupling, biphenyl-coupling, substituted phenylsulfide coupling, tri-functional phenylsulfide, and naphtyl coupling, which are illustrated below by chemical formulas 2 to 10. The content of the copolymer component is preferably less than 30 mol %, but, when a coupling more than a tri-functional coupling is included, the content is preferably less than 5 mol %, more preferably less than 3 mol %.
(in the formula, R represents an alkyl group, a nitro group, a phenyl group or a alcoxy group)
It is noted that the polyarylenesulfide resin (A) used in the present invention has a superior reactivity with the (B) or (C) components a superior compatibility with the (B) and (C) (here, compatibility means a capability of being smaller particles size of the component (B), (C) or (D)), and the resin (A) is capable of providing the high adhesiveness with the epoxy resin. From the point of view of the above superior reactivity of the (B) and (C) components and high adhesiveness to the cured epoxy resin, it is preferable for the polyarylenesulfide resin to provide the following properties; &Dgr;HCl is not more than 10 &mgr;mol/g, &Dgr;NaOH is within 5 to 30 &mgr;mol/g, and (&Dgr;NaOH-&Dgr;HCl) ≧5 &mgr;mol/g.
Here, &Dgr;HCl, &Dgr;NaOH, and (&Dgr;NaOH-&Dgr;HCl) are obtained by the following measurements.
10 g of polyarylenesulfide resin (A) is stirred after adding 10 mol of 1 mol/l of HCl, and the suspension is filtrated. The separated solid is repeatedly washed by water until the HCl is not detected, and all of filtrate used for washing is collected and HCl in the collected filtrate is titrated by NaOH, and the molar number of HCl is defined as &Dgr;HCl.
Next, the polyarylenesulfide resin (A) after washing by water is again dispersed in distilled water and stirred after adding 10 ml of 1 mol/l of NaOH. The solution is filtrated after stirring, and the filtrated solid is repeatedly washed by water until NaOH is not detected. All the filtrate used for washing is collected and NaOH in the filtrate is titrated by HCl, and the molar number of NaO
Adachi Tsuneyuki
Kawashima Kiyotaka
Armstrong Westerman & Hattori, LLP
Dainippon Ink and Chemicals Inc.
Sellers Robert E. L.
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